/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2015 Damien Zammit <damien@zamaudio.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <arch/io.h>
#include <cbmem.h>
#include <console/console.h>
#include <cpu/x86/cache.h>
#include <cpu/x86/mtrr.h>
#include <delay.h>
#include <halt.h>
#include <lib.h>
#include "iomap.h"
#if IS_ENABLED(CONFIG_SOUTHBRIDGE_INTEL_I82801GX)
#include <southbridge/intel/i82801gx/i82801gx.h> /* smbus_read_byte */
#else
#include <southbridge/intel/i82801jx/i82801jx.h> /* smbus_read_byte */
#endif
#include "x4x.h"
#include <pc80/mc146818rtc.h>
#include <spd.h>
#include <string.h>
#include <device/dram/ddr2.h>
#include <mrc_cache.h>

#define MRC_CACHE_VERSION 0

static inline int spd_read_byte(unsigned int device, unsigned int address)
{
	return smbus_read_byte(device, address);
}

static enum cb_err verify_spds(const u8 *spd_map,
			const struct sysinfo *ctrl_cached)
{
	int i;
	u8 raw_spd[256] = {};
	u16 crc;

	for (i = 0; i < TOTAL_DIMMS; i++) {
		if (!(spd_map[i]))
			continue;
		int len = smbus_read_byte(spd_map[i], 0);
		if (len < 0 && ctrl_cached->dimms[i].card_type
				== RAW_CARD_UNPOPULATED)
			continue;
		if (len > 0 && ctrl_cached->dimms[i].card_type
				== RAW_CARD_UNPOPULATED)
			return CB_ERR;

		if (ctrl_cached->spd_type == DDR2) {
			i2c_block_read(spd_map[i], 64, 9, &raw_spd[64]);
			i2c_block_read(spd_map[i], 93, 6, &raw_spd[93]);
			crc = spd_ddr2_calc_unique_crc(raw_spd, len);
		} else { /*
			  * DDR3: TODO ddr2.h and ddr3.h
			  * cannot be included directly
			  */
			crc = 0;
			// i2c_block_read(spd_map[i], 117, 11, &raw_spd[117]);
			// crc = spd_ddr3_calc_unique_crc(raw_spd, len);
		}
		if (crc != ctrl_cached->dimms[i].spd_crc)
			return CB_ERR;
	}
	return CB_SUCCESS;
}

struct abs_timings {
	u32 min_tclk;
	u32 min_tRAS;
	u32 min_tRP;
	u32 min_tRCD;
	u32 min_tWR;
	u32 min_tRFC;
	u32 min_tWTR;
	u32 min_tRRD;
	u32 min_tRTP;
	u32 min_tCLK_cas[8];
	u32 cas_supported;
};

#define CTRL_MIN_TCLK_DDR2 TCK_400MHZ

static void select_cas_dramfreq_ddr2(struct sysinfo *s,
				const struct abs_timings *saved_timings)
{
	u8 try_cas;
	/* Currently only these CAS are supported */
	u8 cas_mask = SPD_CAS_LATENCY_DDR2_5 | SPD_CAS_LATENCY_DDR2_6;

	cas_mask &= saved_timings->cas_supported;
	try_cas = spd_get_msbs(cas_mask);

	while (cas_mask & (1 << try_cas) && try_cas > 0) {
		s->selected_timings.CAS = try_cas;
		s->selected_timings.tclk = saved_timings->min_tCLK_cas[try_cas];
		if (s->selected_timings.tclk >= CTRL_MIN_TCLK_DDR2 &&
				saved_timings->min_tCLK_cas[try_cas] !=
				saved_timings->min_tCLK_cas[try_cas - 1])
			break;
		try_cas--;
	}


	if ((s->selected_timings.CAS < 3) || (s->selected_timings.tclk == 0))
		die("Could not find common memory frequency and CAS\n");

	switch (s->selected_timings.tclk) {
	case TCK_200MHZ:
	case TCK_266MHZ:
		/* FIXME: this works on vendor BIOS */
		die("Selected dram frequency not supported\n");
	case TCK_333MHZ:
		s->selected_timings.mem_clk = MEM_CLOCK_667MHz;
		break;
	case TCK_400MHZ:
		s->selected_timings.mem_clk = MEM_CLOCK_800MHz;
		break;
	}
}

static void mchinfo_ddr2(struct sysinfo *s)
{
	const u32 eax = cpuid_ext(0x04, 0).eax;
	printk(BIOS_WARNING, "%d CPU cores\n", ((eax >> 26) & 0x3f) + 1);

	u32 capid = pci_read_config16(PCI_DEV(0, 0, 0), 0xe8);
	if (!(capid & (1<<(79-64))))
		printk(BIOS_WARNING, "iTPM enabled\n");

	capid = pci_read_config32(PCI_DEV(0, 0, 0), 0xe4);
	if (!(capid & (1<<(57-32))))
		printk(BIOS_WARNING, "ME enabled\n");

	if (!(capid & (1<<(56-32))))
		printk(BIOS_WARNING, "AMT enabled\n");

	s->max_ddr2_mhz = 800; // All chipsets in x4x support up to 800MHz DDR2
	printk(BIOS_WARNING, "Capable of DDR2 of %d MHz or lower\n", s->max_ddr2_mhz);

	if (!(capid & (1<<(48-32))))
		printk(BIOS_WARNING, "VT-d enabled\n");
}

static int ddr2_save_dimminfo(u8 dimm_idx, u8 *raw_spd,
		struct abs_timings *saved_timings, struct sysinfo *s)
{
	struct dimm_attr_ddr2_st decoded_dimm;
	int i;

	if (spd_decode_ddr2(&decoded_dimm, raw_spd) != SPD_STATUS_OK) {
		printk(BIOS_DEBUG, "Problems decoding SPD\n");
		return CB_ERR;
	}

	if (IS_ENABLED(CONFIG_DEBUG_RAM_SETUP))
		dram_print_spd_ddr2(&decoded_dimm);

	if (!(decoded_dimm.width & (0x08 | 0x10))) {

		printk(BIOS_ERR,
			"DIMM%d Unsupported width: x%d. Disabling dimm\n",
			dimm_idx, s->dimms[dimm_idx].width);
		return CB_ERR;
	}
	s->dimms[dimm_idx].width = (decoded_dimm.width >> 3) - 1;
	/*
	 * This boils down to:
	 * "Except for the x16 configuration, all DDR2 devices have a
	 * 1KB page size. For the x16 configuration, the page size is 2KB
	 * for all densities except the 256Mb device, which has a 1KB page
	 * size." Micron, 'TN-47-16 Designing for High-Density DDR2 Memory'
	 */
	s->dimms[dimm_idx].page_size = s->dimms[dimm_idx].width *
		 (1 << decoded_dimm.col_bits);

	switch (decoded_dimm.banks) {
	case 4:
		s->dimms[dimm_idx].n_banks = N_BANKS_4;
		break;
	case 8:
		s->dimms[dimm_idx].n_banks = N_BANKS_8;
		break;
	default:
		printk(BIOS_ERR,
			"DIMM%d Unsupported #banks: x%d. Disabling dimm\n",
			 dimm_idx, decoded_dimm.banks);
		return CB_ERR;
	}

	s->dimms[dimm_idx].ranks = decoded_dimm.ranks;
	s->dimms[dimm_idx].rows = decoded_dimm.row_bits;
	s->dimms[dimm_idx].cols = decoded_dimm.col_bits;

	saved_timings->cas_supported &= decoded_dimm.cas_supported;

	saved_timings->min_tRAS =
		MAX(saved_timings->min_tRAS, decoded_dimm.tRAS);
	saved_timings->min_tRP =
		MAX(saved_timings->min_tRP, decoded_dimm.tRP);
	saved_timings->min_tRCD =
		MAX(saved_timings->min_tRCD, decoded_dimm.tRCD);
	saved_timings->min_tWR =
		MAX(saved_timings->min_tWR, decoded_dimm.tWR);
	saved_timings->min_tRFC =
		MAX(saved_timings->min_tRFC, decoded_dimm.tRFC);
	saved_timings->min_tWTR =
		MAX(saved_timings->min_tWTR, decoded_dimm.tWTR);
	saved_timings->min_tRRD =
		MAX(saved_timings->min_tRRD, decoded_dimm.tRRD);
	saved_timings->min_tRTP =
		MAX(saved_timings->min_tRTP, decoded_dimm.tRTP);
	for (i = 0; i < 8; i++) {
		if (!(saved_timings->cas_supported & (1 << i)))
			saved_timings->min_tCLK_cas[i] = 0;
		else
			saved_timings->min_tCLK_cas[i] =
				MAX(saved_timings->min_tCLK_cas[i],
					decoded_dimm.cycle_time[i]);
	}

	s->dimms[dimm_idx].spd_crc = spd_ddr2_calc_unique_crc(raw_spd,
					spd_decode_spd_size_ddr2(raw_spd[0]));
	return CB_SUCCESS;
}

static void select_discrete_timings(struct sysinfo *s,
				const struct abs_timings *timings)
{
	s->selected_timings.tRAS = DIV_ROUND_UP(timings->min_tRAS,
						s->selected_timings.tclk);
	s->selected_timings.tRP = DIV_ROUND_UP(timings->min_tRP,
						s->selected_timings.tclk);
	s->selected_timings.tRCD = DIV_ROUND_UP(timings->min_tRCD,
						s->selected_timings.tclk);
	s->selected_timings.tWR = DIV_ROUND_UP(timings->min_tWR,
						s->selected_timings.tclk);
	s->selected_timings.tRFC = DIV_ROUND_UP(timings->min_tRFC,
						s->selected_timings.tclk);
	s->selected_timings.tWTR = DIV_ROUND_UP(timings->min_tWTR,
						s->selected_timings.tclk);
	s->selected_timings.tRRD = DIV_ROUND_UP(timings->min_tRRD,
						s->selected_timings.tclk);
	s->selected_timings.tRTP = DIV_ROUND_UP(timings->min_tRTP,
						s->selected_timings.tclk);
}
static void print_selected_timings(struct sysinfo *s)
{
	printk(BIOS_DEBUG, "Selected timings:\n");
	printk(BIOS_DEBUG, "\tFSB:  %dMHz\n",
		fsb2mhz(s->selected_timings.fsb_clk));
	printk(BIOS_DEBUG, "\tDDR:  %dMHz\n",
		ddr2mhz(s->selected_timings.mem_clk));

	printk(BIOS_DEBUG, "\tCAS:  %d\n", s->selected_timings.CAS);
	printk(BIOS_DEBUG, "\ttRAS: %d\n", s->selected_timings.tRAS);
	printk(BIOS_DEBUG, "\ttRP:  %d\n", s->selected_timings.tRP);
	printk(BIOS_DEBUG, "\ttRCD: %d\n", s->selected_timings.tRCD);
	printk(BIOS_DEBUG, "\ttWR:  %d\n", s->selected_timings.tWR);
	printk(BIOS_DEBUG, "\ttRFC: %d\n", s->selected_timings.tRFC);
	printk(BIOS_DEBUG, "\ttWTR: %d\n", s->selected_timings.tWTR);
	printk(BIOS_DEBUG, "\ttRRD: %d\n", s->selected_timings.tRRD);
	printk(BIOS_DEBUG, "\ttRTP: %d\n", s->selected_timings.tRTP);
}

static void find_fsb_speed(struct sysinfo *s)
{
	switch (MCHBAR32(0xc00) & 0x7) {
	case 0x0:
		s->max_fsb = FSB_CLOCK_1066MHz;
		break;
	case 0x2:
		s->max_fsb = FSB_CLOCK_800MHz;
		break;
	case 0x4:
		s->max_fsb = FSB_CLOCK_1333MHz;
		break;
	default:
		s->max_fsb = FSB_CLOCK_800MHz;
		printk(BIOS_WARNING, "Can't detect FSB, setting 800MHz\n");
		break;
	}
	s->selected_timings.fsb_clk = s->max_fsb;
}

static void decode_spd_select_timings(struct sysinfo *s)
{
	unsigned int device;
	u8 dram_type_mask = (1 << DDR2) | (1 << DDR3);
	u8 dimm_mask = 0;
	u8 raw_spd[256];
	int i, j;
	struct abs_timings saved_timings;
	memset(&saved_timings, 0, sizeof(saved_timings));
	saved_timings.cas_supported = UINT32_MAX;

	FOR_EACH_DIMM(i) {
		s->dimms[i].card_type = RAW_CARD_POPULATED;
		device = s->spd_map[i];
		if (!device) {
			s->dimms[i].card_type = RAW_CARD_UNPOPULATED;
			continue;
		}
		switch (spd_read_byte(s->spd_map[i], SPD_MEMORY_TYPE)) {
		case DDR2SPD:
			dram_type_mask &= 1 << DDR2;
			s->spd_type = DDR2;
			break;
		case DDR3SPD:
			dram_type_mask &= 1 << DDR3;
			s->spd_type = DDR3;
			break;
		default:
			s->dimms[i].card_type = RAW_CARD_UNPOPULATED;
			continue;
		}
		if (!dram_type_mask)
			die("Mixing up dimm types is not supported!\n");

		printk(BIOS_DEBUG, "Decoding dimm %d\n", i);
		if (s->spd_type == DDR2){
			printk(BIOS_DEBUG,
				"Reading SPD using i2c block operation.\n");
			if (i2c_block_read(device, 0, 128, raw_spd) != 128) {
				printk(BIOS_DEBUG, "i2c block operation failed,"
					" trying smbus byte operation.\n");
				for (j = 0; j < 128; j++)
					raw_spd[j] = spd_read_byte(device, j);
			}
			if (ddr2_save_dimminfo(i, raw_spd, &saved_timings, s)) {
				printk(BIOS_WARNING,
					"Encountered problems with SPD, "
					"skipping this DIMM.\n");
				s->dimms[i].card_type = RAW_CARD_UNPOPULATED;
				continue;
			}
		} else { /* DDR3: not implemented so don't decode */
			die("DDR3 support is not implemented\n");
		}
		dimm_mask |= (1 << i);
	}
	if (!dimm_mask)
		die("No memory installed.\n");

	if (s->spd_type == DDR2)
		select_cas_dramfreq_ddr2(s, &saved_timings);
	select_discrete_timings(s, &saved_timings);
}

static void find_dimm_config(struct sysinfo *s)
{
	int chan, i;

	FOR_EACH_POPULATED_CHANNEL(s->dimms, chan) {
		FOR_EACH_POPULATED_DIMM_IN_CHANNEL(s->dimms, chan, i) {
			int dimm_config;
			if (s->dimms[i].ranks == 1) {
				if (s->dimms[i].width == 0)	/* x8 */
					dimm_config = 1;
				else				/* x16 */
					dimm_config = 3;
			} else {
				if (s->dimms[i].width == 0)	/* x8 */
					dimm_config = 2;
				else
					die("Dual-rank x16 not supported\n");
			}
			s->dimm_config[chan] |=
				dimm_config << (i % DIMMS_PER_CHANNEL) * 2;
		}
		printk(BIOS_DEBUG, "  Config[CH%d] : %d\n", chan,
			s->dimm_config[chan]);
	}

}

static void checkreset_ddr2(int boot_path)
{
	u8 pmcon2;
	u32 pmsts;

	if (boot_path >= 1) {
		pmsts = MCHBAR32(PMSTS_MCHBAR);
		if (!(pmsts & 1))
			printk(BIOS_DEBUG,
				"Channel 0 possibly not in self refresh\n");
		if (!(pmsts & 2))
			printk(BIOS_DEBUG,
				"Channel 1 possibly not in self refresh\n");
	}

	pmcon2 = pci_read_config8(PCI_DEV(0, 0x1f, 0), 0xa2);

	if (pmcon2 & 0x80) {
		pmcon2 &= ~0x80;
		pci_write_config8(PCI_DEV(0, 0x1f, 0), 0xa2, pmcon2);

		/* do magic 0xf0 thing. */
		u8 reg8 = pci_read_config8(PCI_DEV(0, 0, 0), 0xf0);
		pci_write_config8(PCI_DEV(0, 0, 0), 0xf0, reg8 & ~(1 << 2));
		reg8 = pci_read_config8(PCI_DEV(0, 0, 0), 0xf0);
		pci_write_config8(PCI_DEV(0, 0, 0), 0xf0, reg8 |  (1 << 2));

		printk(BIOS_DEBUG, "Reset...\n");
		outb(0xe, 0xcf9);
		asm ("hlt");
	}
	pmcon2 |= 0x80;
	pci_write_config8(PCI_DEV(0, 0x1f, 0), 0xa2, pmcon2);
}

/**
 * @param boot_path: 0 = normal, 1 = reset, 2 = resume from s3
 */
void sdram_initialize(int boot_path, const u8 *spd_map)
{
	struct sysinfo s, *ctrl_cached;
	u8 reg8;
	int fast_boot, cbmem_was_inited, cache_not_found;
	struct region_device rdev;

	printk(BIOS_DEBUG, "Setting up RAM controller.\n");

	pci_write_config8(PCI_DEV(0, 0, 0), 0xdf, 0xff);

	memset(&s, 0, sizeof(struct sysinfo));

	cache_not_found = mrc_cache_get_current(MRC_TRAINING_DATA,
						MRC_CACHE_VERSION, &rdev);

	if (cache_not_found || (region_device_sz(&rdev) < sizeof(s))) {
		if (boot_path == BOOT_PATH_RESUME) {
			/* Failed S3 resume, reset to come up cleanly */
			outb(0x6, 0xcf9);
			halt();
		}
		ctrl_cached = NULL;
	} else {
		ctrl_cached = rdev_mmap_full(&rdev);
	}

	/* verify MRC cache for fast boot */
	if (boot_path != BOOT_PATH_RESUME && ctrl_cached) {
		/* check SPD checksum to make sure the DIMMs haven't been
		 * replaced */
		fast_boot = verify_spds(spd_map, ctrl_cached) == CB_SUCCESS;
		if (!fast_boot)
			printk(BIOS_DEBUG, "SPD checksums don't match,"
				" dimm's have been replaced\n");
	} else {
		fast_boot = boot_path == BOOT_PATH_RESUME;
	}

	if (fast_boot) {
		printk(BIOS_DEBUG, "Using cached raminit settings\n");
		memcpy(&s, ctrl_cached, sizeof(s));
		s.boot_path = boot_path;
		mchinfo_ddr2(&s);
		print_selected_timings(&s);
	} else {
		s.boot_path = boot_path;
		s.spd_map[0] = spd_map[0];
		s.spd_map[1] = spd_map[1];
		s.spd_map[2] = spd_map[2];
		s.spd_map[3] = spd_map[3];
		checkreset_ddr2(s.boot_path);

		/* Detect dimms per channel */
		reg8 = pci_read_config8(PCI_DEV(0, 0, 0), 0xe9);
		printk(BIOS_DEBUG, "Dimms per channel: %d\n",
			(reg8 & 0x10) ? 1 : 2);

		mchinfo_ddr2(&s);

		find_fsb_speed(&s);
		decode_spd_select_timings(&s);
		print_selected_timings(&s);
		find_dimm_config(&s);
	}

	switch (s.spd_type) {
	case DDR2:
		raminit_ddr2(&s, fast_boot);
		break;
	case DDR3:
		// FIXME Add: raminit_ddr3(&s);
		break;
	default:
		die("Unknown DDR type\n");
		break;
	}

	reg8 = pci_read_config8(PCI_DEV(0, 0x1f, 0), 0xa2);
	pci_write_config8(PCI_DEV(0, 0x1f, 0), 0xa2, reg8 & ~0x80);

	reg8 = pci_read_config8(PCI_DEV(0, 0, 0), 0xf4);
	pci_write_config8(PCI_DEV(0, 0, 0), 0xf4, reg8 | 1);
	printk(BIOS_DEBUG, "RAM initialization finished.\n");

	cbmem_was_inited = !cbmem_recovery(s.boot_path == BOOT_PATH_RESUME);
	if (!fast_boot)
		mrc_cache_stash_data(MRC_TRAINING_DATA, MRC_CACHE_VERSION,
					&s, sizeof(s));
	if (s.boot_path == BOOT_PATH_RESUME && !cbmem_was_inited) {
		/* Failed S3 resume, reset to come up cleanly */
		outb(0x6, 0xcf9);
		halt();
	}
}
